1 /*
 2  * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
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23  */
24 
25 #include "gc/g1/g1CodeBlobClosure.hpp"
26 #include "gc/g1/g1OopClosures.hpp"
27 #include "memory/iterator.hpp"
28 
29 class G1CollectedHeap;
30 class G1ParScanThreadState;
31 
32 // Simple holder object for a complete set of closures used by the G1 evacuation code.
33 template <bool should_mark>
34 class G1SharedClosures {
35 public:
36   G1ParCopyClosure<G1BarrierNone, should_mark> _oops;
37   G1ParCopyClosure<G1BarrierCLD,  should_mark> _oops_in_cld;
38   // We do not need (and actually should not) collect oops from nmethods into the
39   // optional collection set as we already automatically collect the corresponding
40   // nmethods in the region's strong code roots set. So set G1BarrierNoOptRoots in
41   // this closure.
42   // If these were present there would be opportunity for multiple threads to try
43   // to change this oop* at the same time. Since embedded oops are not necessarily
44   // word-aligned, this could lead to word tearing during update and crashes.
45   G1ParCopyClosure<G1BarrierNoOptRoots, should_mark> _oops_in_nmethod;
46 
47   G1CLDScanClosure                _clds;
48   G1CodeBlobClosure               _strong_codeblobs;
49   G1CodeBlobClosure               _weak_codeblobs;
50 
51   G1SharedClosures(G1CollectedHeap* g1h, G1ParScanThreadState* pss, bool process_only_dirty) :
52     _oops(g1h, pss),
53     _oops_in_cld(g1h, pss),
54     _oops_in_nmethod(g1h, pss),
55     _clds(&_oops_in_cld, process_only_dirty),
56     _strong_codeblobs(pss->worker_id(), &_oops_in_nmethod, should_mark, true),
57     _weak_codeblobs(pss->worker_id(), &_oops_in_nmethod, should_mark, false)
58 
59     {}
60 };